Non-corrosive sulfur-liquid hydrocarbon slurry containing an asphaltenic compound

ABSTRACT

AN IMPROVED NON-CORROSIVE SULFUR-LIQUID HYDROCARBON SLURRY COMPOSITION AND METHOD OF PREPPARING SAID SLURRY FOR TRANSPORTATION IN SUITABLE VEHICLES SUCH AS PIPELINES WITHOUT CAUSING PLUGGING AND CORROSION.

United States ABSTRACT OF THE DISCLOSURE An improved non-corrosivesulfur-liquid hydrocarbon slurry composition and method of preparingsaid slurry for transportation in suitable vehicles such as pipelineswithout causing plugging and corrosion.

CROSS-REFERENCE This is a continuation-in-part of copending patentapplication Ser. No. 772,008, filed Oct. 30, 1968, now U.S. Pat.3,597,005.

FIELD OF THE INVENTION The invention raltes to a new, improved and novelnoncorrosive, non-plugging sulfur-liquid hydrocarbon slurry compositionhaving incorporated therein a small amount of an aqueous solutioncontaining an asphaltenic material, said slurry composition beingparticularly designed for transportation through conduits such aspipelines or vehicles such as tankers, etc.

BACKGROUND OF THE INVENTION The invention relates to a new, improved andnovel nonslurry in pipelines is well known in the art as noted byreference to U.S. Pats. 2,798,772; 2,917,345 or 2,947,578 or asdescribed in Pipeline Industry, June 1967, pp. 5-8-60 or Chem. Eng.Prog., vol. 61, No. 2, 72, 1965. In form- 4 ing a sulfur-hydrocarbonslurry, the sulfur is generally sprayed in molten form into either wateror a hydrocarbon in an amount suflicient to form a slurry suitable fortransportation through a pipeline. Formation of a stable noncorrosivesulfur-containing slurry wherein the sulfur does not undergo anyundesirable change or the slurry does not exhibit a tendency to Widevariation in viscosity is essential to the process in addition to otherproblems which may be encountered during and after transportation of theslurry through a pipeline. Thus, separation of the sulfur from thecarrier fluid results in plating or coating of the sulfur vessel walls,e.g. pipeline walls causing corrosion and plugging of the pipeline.Viscosity changes in the slurry due to pressure and temperaturevariations encountered under such conditions results in increase inpumping power which increases operation costs, etc. These are a few ofthe problems normally encountered and which must be avoided intransporting sulfur-liquid hydrocarbon slurries through pipelines orother vehicles. However, a most troublesome one is that of corrosionencountered in the preparation, transportation, and recovery 0 of suchslurry systems for if excessive corrosion is encountered in any of thesethree phases then the slurry system cannot be put into operation.

Although these are serious problems for consideration in the preparationand transportation and recovery of sul- 5 fur, nevertheless if thecorrosion problem is controlled, it can be made to be an effective andeconomically attractive means of preparing and transporting suchslurries particularly since sulfur is normally recovered or obtainedfrom isolated, remote and inaccessible areas. As noted above, a numberof methods have been proposed 3,745,120 Fatented July 10, 1973 ice forpipeline transportation of sulfur slurries such as by injecting moltensulfur into water or a liquid hydrocarbon thereby forming a sulfurslurry for pipeline transportation. Such means for preparing andtransporting sulfur do not overcome the corrosion, coating or pluggingproblems described above.

An object of the present invention is to prepare for transport sulfur asa sulfur-liquid hydrocarbon slurry composition which is non-corrosive,stable and flowable.

Another object of the present invention is to transport through apipeline sulfur-liquid hydrocarbon slurries without causing sulfurcoating, deposition or plugging or corrosion of the pipeline.

Still another object of this invention is to form a slurry of sulfur ina liquid hydrocarbon medium, which when formed is stable, non-corrosive,does not tend to cause pipeline plugging when said slurry is transportedthrough a pipeline and from which the sulfur can be readily recovered asessentially pure sulfur.

Another object is to transfer sulfur as a liquid hydrocarbon slurry bypipeline over great distances reducing pumping and handling costs.

Other objects will be apparent from the following description.

SUMMARY OF THE INVENTION The invention relates to a new, improved andnovel non-corrosive, non-plugging sulfur-liquid hydrocarbon slurrycomposition containing therein a small amount of an aqueous solutioncontaining a nitrogen organic compound having at least one amino oramino-amide or imidazole group in the molecule, said slurry compositionbeing particularly designed for transportation through conduits such aspipelines or vehicles such as tankers, etc.

Specifically, the present invention is directed to an improved, noveland new technique for preparing for vehicle transportation such aspipeline transportation of a sulfurliquid hydrocarbon slurry throughpipelines over great distances without causing corrosion, coating,deposition or plugging of the pipeline due to the tendency of sulfurunder such conditions to adhere to the pipeline walls because oftemperature, pressure and other variable conditions to corrode and plugsaid lines; by admixing or adding or injecting prior to or afterinjection of a sulfur-liquid hydrocarbon slurry into the pipeline, asmall amount of 0.1 to 10% by weight, perferably between about 0.5 toabout 5% by weight, of an aqueous solution basis total slurry and fromabout 20 to about 5000 ppm. basis oil phase of an asphaltenic materialextracted from crude oil by any suitable means or an asphalt containing20 to about 5000 ppm. basis oil phase of asphaltenic material.Asphaltenes can include materials described in The Chemical Constituentsof PetroleumSachanen, Chapter 9 and include petroleum resins,asphaltenes, asphaltogenic acids their derivatives and mixtures thereofand include materials described in the Journal of the Institute ofPetroleum, April 1968, pages 107-114 and February 1968, pages -53 or asdescribed in U.S. Pats. 3,275,076; 3,284,340; or 3,336,146 and thesematerials can be separated from petroleums by methods described in U.S.Pats. 3,364,138 and 3,368,876. The asphaltenes as defined should bepresent in the final mixture in an amount preferably not exceeding 2000ppm. basis oil phase and the additive can be injected when necessary invarious places along the pipeline where indications are that corrosionor plugging of the line might take place. Any corrosion and pluggingdetection means known in the art can be used for this purpose. It hasbeen noted that by injection of l5% by weight of an aqueous solutionbasis total slurry and a small amount (20-2000 p.p.m. basis oil phase ofan asphaltene as defined into a pipeline transporting a sulfur-liquidhydrocarbon slurry in which the sulfur content of the slurry can varyfrom about 10% by weight sulfur, inhibits corrosion and preventsplugging of 30 and 70% by weight sulfur, inhibits corrosion and preventsplugging of the line due to sulfur deposition on the walls of thepipeline, resulting in improved flow of the slurry at reduced pumpingcost. A preferred plugging and corrosion preventing composition forsulfur-liquid hydrocarbon slurries being pipeline transported is theaddition to such slurries of from about 1 to 5% by weight water basistotal slurry and 20-2000 p.p.m. basis oil phase of an asphaltenicmaterial selected from the group consisting of asphalt, asphaltenes,asphaltogenic acid and mixtures thereof.

The sulfur-liquid hydrocarbon slurry can be made by any suitable meanssuch as described in U.S. Pat. 2,798,- 772, or 3,443,837. It ispreferred that methods for making the sulfur-liquid hydrocarbon slurrybe used in which the sulfur is produced in spherical form since thisfacilitates the stable dispersion and suspension of the sulfur in theliquid hydrocarbon carrier and inhibits attrition and reduces friction.The phase transfer method for making the sulfur slurry as described inthe above copending application comprises first forming a sulfur-aqueousliquid (water) slurry and thereafter phase transferring the sulfurparticles from the aqueous liquid into a liquid hydrocarbon. In thisprocess the phase transformation to form the sulfur-hydrocarbon slurrycan be so controlled that a small amount (1-5% by weight) water basistotal slurry is transferred with the sulfur-water phase into thehydrocarbon phase and thereafter an asphaltenic material can be added toaccomplish the desired ends of the present invention. Slurries thusprepared contain sulfur in particle form of 5-5000 microns, preferably30350 microns and are spherical in shape.

The hydrocarbon carrier for the sulfur can be any liquid hydrocarbonranging from a light petroleum fraction such as liquefied petrolem gas(LPG), fuel oil, gasoline, kerosene, petroleum distillates condensates,crude oil and mixtures thereof. Preferred are liquid hydrocarbonscontaining at least by weight or higher of aromatics, preferably about-30% by weight aromatic enriched kerosene or crude oil or crude oilcondensate fractions containing l520% by weight aromatics which includemonoand polyaromatic hydrocarbons.

At the terminal end of the line the aqueous solution can be readilyseparated from the sulfur-hydrocarbon system by suitable phaseseparation, distillation or the like.

PREFERRED EMBODIMENT OF THE INVENTION 40-60% by weight sulfur in (a)aromatic (17% by weight) enriched kerosene or (b) a petroleum condensateor (c) a blend of (b) and crude oil slurries, were prepared by phasetransfer by first injecting molten sulfur into an aqueous liquid such aswater and thereafter contacting the slurry thus formed with hydrocarbons(a), (b) or (c) to effect phase transfer of the sulfur particles intothe hydrocarbon, and injecting this slurry into a pipeline followed byinjection of 2% by weight water basis oil phase and about 20800 p.p.m.basis oil phase of an asphaltene additive shown in Table 2.Sulfur-hydrocarbon slurries thus formed in the presence of the water andan asphaltene additive of the present invention do not corrode or plugpipelines. Instead of using the phase transfer technique for making theslurry, the molten sulfur can be injected in the hydrocarbons (a), (b)or (c) directly and thereafter admixed with the aqueous solution andadditive.

An advantage of the present process for transporting through pipelinessulfur-liquid hydrocarbon slurries is that the slurry can be alsoprepared by directed injection of molten sulfur into a suitable liquidhydrocarbon as described in U.S. Pat. 2,798,772 and injecting therein asmall amount of Water and an asphaltene additive so as to preventcorrosion and plugging of the line. Either process as well as otherprocesses can be used to make the sulfur-liquid hydrocarbon slurrydepending on the availability of the liquid carriers. Thus, where wateris available the first process can be used and if not, the second onecan be used.

The corrosive effect of added or adventitious water on sulfur-liquidhydrocarbon slurries is evident from the data presented in Table 1 andthe selectiveness and unexpected effect of asphaltenic additives of thisinvention as corrosion preventive agents is shown in Table 2.

The slurry tested comprised 40% by weight sulfur and 60% hydrocarbon andthe conditions for the corrosion test were as follows:

CORROSION BY SULFUR SLURRIES Conditions:

TABLE 1 Sulfur slurry corrosion as a function of water concentrationConditions: As above. 40% W. Waterton sulfur/kerosene with 17% w.aromatics.

Water concentration, Corrosion rate,

percent W3: mils/yr. 0 1 0.28 50 11 Concentration of added water, basisoil. b From weight loss and exposure time. Corrosion rates have not beencorrected for weight loss due to cleaning.

TABLE 2 Effect of asphaltenes on sulfur slurry corrosion Conditions: Asin Table 1. 40% w. Jumping Pound sulfur/kerosene with aromatics plus 2%w. H O (basis oil).

Additive Corrosion rate, mpy.

Medicine River Crude Asphaltenes b 210 p.p.m. 8.8

0.1 percent w. 5 Asphalt 0.061 percent w. containing p.p.m.

asphaltenes 4 5 a From weight loss and exposure time. Corrosion rateshave not been corrected for weight loss due to cleaning.

b Produced by heptane precipitation.

0 Additions are basis oil phase.

At the terminal end of the line the water phase can be readily removedby phase separation and the sulfur can be removed from the liquidhydrocarbon by suitable means such as described in U.S. Pat. 2,798,772and the sulfur, purified by methods as described in U.S. Pats. 2,809,885and 3,489,671 which latter patent teaches treating oil contaminatedsulfur with an aqueous solution containing a mixture of alkalihydrosulfide and corresponding hydroxide, e.g., ammonium hydrosulfideand ammonium hydroxide, or by other suitable means such as sulfur can berecovered from the oil slurry by filtration of molten sulfur andliquid-liquid extraction with a hydrocarbon solvent containing 10-50% byweight aromatic. Thus, at the receiving terminal the sulfur slurry canbe filtered and washed. The recovered sulfur is then melted and purifiedby liquid-liquid extraction with an aromatic hydrocarbon such as cumene.Also, if desired, the filtered sulfur can be steam stripped to recoverbright yellow sulfur.

The foregoing description of the invention is merely intended to beexplanatory thereof. Various changes in the details of the describedmethod may be made within the scope of the appended claims withoutdeparting from the spirit of the invention.

I claim as my invention:

1. A method of preparing a sulfur-liquid hydrocarbon slurry compositionand inhibiting the undesired corrosive effects of the slurry on pipelineWalls comprising spraying at least 10% of molten sulfur into a liquidhydrocarbon and thereafter admixing therein a small amount of from 0.1%to 10% of an aqueous solution containing from about 20 to about 5000p.p.m. basis oil phase of an asphaltenic compound extracted from crudeoil.

2. The method of claim 1 wherein the liquid hydrocarbon is petroleum oiland the asphaltenic compound is asphaltene.

3. The method of claim 2 wherein the oil is crude oil.

References Cited UNITED STATES PATENTS 2,343,860 3/1944 Eencowitz 252-312,204,967 6/1940 Moser 252-83 FOREIGN PATENTS 129,132 7/1919 GreatBritain 25231 OTHER REFERENCES Chemical Abstracts, vol. 55, col. 21554b.Chemical Abstracts, vol. 46, col. 2785i and vol. 59, col. 12564f.

JOHN D. WELSH, Primary Examiner U.S. Cl. X.R.

